Builder.io Gen2 SDKs through versions 5.2.11 and 0.25.13 contain a prototype pollution vulnerability in the unflatten helper that processes builder.userAttributes query parameters without prototype guards. Attackers can craft preview links with __proto__ or prototype segments to pollute Object.prototype in a visitor's browser when the SDK processes the malicious URL.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
Passive
Minimal interaction
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
Low
Partial data modification
Availability
Low
Partial disruption
CVSS Vector v4.0
Weakness Type (CWE)
References 5
https://github.com/BuilderIO/builder
disclosure@vulncheck.com
https://github.com/BuilderIO/builder/blob/main/packages/sdks/src/functions/get-…
disclosure@vulncheck.com
https://github.com/BuilderIO/builder/blob/main/packages/sdks/src/helpers/flatte…
disclosure@vulncheck.com
https://github.com/BuilderIO/builder/issues/4824
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/builder-io-gen2-sdks-through-5.2.11-protot…
disclosure@vulncheck.com